### Steps to reproduce

* Have required project attributes configured that are also "For all projects"

* The don't have a default value

* Sending `POST /api/v3/projects` with


Begin of the insertion```textEnd of the insertion Begin of the deletion ```End of the deletion
{
"name": "A project created via the api"
}
```

* This will return errors


```text
{
"_type": "Error",
"errorIdentifier": "urn:openproject-org:api:v3:errors:MultipleErrors",
"message": "Multiple field constraints have been violated.",
"_embedded": {
"errors": [
{
"_type": "Error",
"errorIdentifier": "urn:openproject-org:api:v3:errors:PropertyConstraintViolation",
"message": "Admin only cf (required) can't be blank.",
"_embedded": {
"details": {
"attribute": "customField676"
}
}
},
{
"_type": "Error",
"errorIdentifier": "urn:openproject-org:api:v3:errors:PropertyConstraintViolation",
"message": "Required List cf (for all) can't be blank.",
"_embedded": {
"details": {
"attribute": "customField514"
}
}
},
{
"_type": "Error",
"errorIdentifier": "urn:openproject-org:api:v3:errors:PropertyConstraintViolation",
"message": "Required date cf (not for all) can't be blank.",
"_embedded": {
"details": {
"attribute": "customField677"
}
}
}
]
}
}
```

* Send another request with


```text
{
"customField525": 5,
"name": "A project created via the api"
}
```

Please notice that this is another, non required, non active for all, project custom field

### What is the buggy behavior?

* The project is just created when it shouldn't as it is missing values for those required fields. Begin of the insertion

* Additionally required custom fields without the `is_for_all` flag are also validated, and they shouldn't.End of the insertion


### What is the expected behavior?

1. The required, "for all projects" project attributes should be enforced on project creation Begin of the insertion

2. Do not validate required custom fields with `is_for_all` set to `false`.End of the insertion